Arc extinguishing electrical switch apparatus



Oct. 20, 1953 L. H. MATTHIAS ET AL 2,656,442

ARC EXTINGUISHING ELECTRICAL SWITCH APPARATUS iled Nov. 15, 1950 4Sheets-Sheet 1 MIG @ Inn,

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ARC EXTINGUISHING ELECTRICAL SWITCH APPARATUS Filed Nov. 13, 1950 4Sheets-Sheet 2 INVENTORS a? ,a. 0mm

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ARC EXTINGUISHING ELECTRICAL SWITCH APPARATUS Filed Nov. 13, 1950 4Sheets-Sheet 4 INVENTORS WA? 014m y W pal/MW Patented Oct. 20, 1953 ARCEXTINGUISHING ELECTRICAL SWITCH APPARATUS Lynn H. Matthias, Fox Point,and Hans Petersen, Wauwatosa, Wis., assignors to Allen-Bradley 00.,Milwaukee, Wis., a. corporation of Wisconsin Application November 13,1950, Serial No. 195,276

'7 Claims. 1

This invention relates to arc extinguishing apparatus intended for useas an aid in the interruption of large electrical currents by electricswitches, circuit breakers and the like, and it resides in an improvedarc de-ionizing and cooling apparatus comprising a plurality of spaced,substantially parallel, metallic plates, rigidly united and held in thedesired spaced, open pile relation and electrically insulated from oneanother by means of a rigid mineral dielectric substance, composed of anindurated compound of finely divided hydrated aluminosilicic acid andfinely divided alkaline earth base material, chemically interacted inthe presence of one another and of water while in contact with saidplates, so as to become adhesively bonded thereto; the adherently unitedassemblage being adapted to be located in position with reference toseparable electric contacts so as to accept, cool and deionize areproducts propelled thereinto and formed by movement of said electricalcontacts while under load; the assemblage forming, if desired, a unitaryreplaceable structure easily removed from or installed in a completeswitch or other circuit interrupting structure.

Heretofore assemblages of spaced substantially parallel plates, in openpile relation, disposed adjacent an electrical circuit gap at which anarc may be formed, have been employed With success as a means forreceiving, cooling and de-ionizing the are products which are formed, toaid in extinguishing the arc. The several spaced metallic plates must berigidly held in the desired position and must be electrically insulatedfrom one another in order to attain the result desired. Usually theassemblage is mechanically clamped in assembled form by through-boltsemploying insulating materia1 in the form of washers to preserve thespacing desired and to interpose the electrical insulation which isessential. A disadvantage of such structures arises out of thedifficulty of setting up sufiicient clamping pressure to insure apermanently rigid structure without imposing destructive stresses on thesomewhat brittle electrical insulation material which must be employed.A further disadvantage resides in the difficulty of insuring the absenceof all small access voids through which the arc might penetrate to makeelectrical contact with the mechanical through-bolts which are employed.

Some have attempted to employ dielectric or insulating substances, theprimary ingredients of which are composed of organic resins, for thepurpose of obtaining suflicient mechanical strength and for the purposeof adhesively bonding the insulation material to the metallic plates toavoid the difficulties above mentioned. Such structures have theirshortcomings also, since the insulating material is exposed to the veryhot are products, and pyrolysis which ensues results in the formation ofa conductive carbonaceous film on the surface of the insulatingmaterial. This conductive film defeats the purpose of the insulatingmaterial and the arc extinguishing properties of the structure becomeimpaired to the point where circuit interruption is interfered withrather than aided. By reason of these shortcomings of structuresemploying organic resin materials, unitary assemblages of arcde-ionizing plates imbedded in and adhesively bonded by such insulatingmaterials have met with little success.

It is an object of this invention to provide a unitary assemblage ofspaced, arc de-ionizing plates, electrically insulated from one anotherand rigidly held by an insulating material adhesively bonded to theplates, which insulating material is not subject to thermaldecomposition resulting in the formation of electrically conductivesubstances.

Another object of this invention is to provide a unitary assemblage ofarc de-ionizing plates which may be easily inserted in or removed from aswitch structure, as a unitary part, to facilitate repair or replacementof the arc de-ionizing assemblage.

The foregoing and other objects and advantages of this invention willappear from the description following which is set forth by reference tothe accompanying drawings forming a part hereof in which there is setforth by way of illustration and not of limitation one form in which theapparatus of this invention may be constructed.

In the drawings:

Fig. 1 is an end view in elevation and partly in section of anelectrical switch of the type employing an enclosed arc chamber and inwhich an arc de-ionizing assemblage constructed in accordance wtih thisinvention is employed,

Fig. 2 is a top plan view in section of the switch shown in Fig. 1,viewed through the plane 2-2 indicated in Fig. 1,

Fig. 3 is a front view in elevation showing three switches of the typeshown in Figs. 1 and 2 mounted together to be operated by a singlemagnet actuator to form a three phase line contactor, representing onetypical form of apparatus in which the arc de-ionizing assemblage ofthis invention may be employed,

Fig. 4 is a perspective view of one of the arc de-ionizing assemblagesemployed in the switches shown in Figs. 1 to 3 inclusive,

Fig. 5 is a detailed top plan view of one of the metallic platesemployed in making up the arc de-ionizing assemblage shown in Fig. 4,,

Fig. 6 is an end view in elevation and in section of the arc de-ionizingassemblage shown in Fig. 4 viewed through the plane 6-6 there indicated,and

Fig. 7 is an enlarged detailed fragmentary view in section of the arcde-ionizing assemblage shown in Fig. 4 viewed through the plane 7-1there indicated.

In the drawings, in Figs. 1 to 3 inclusive, there is shown one form ofelectrical switch in which the arc cle-ionizing assemblage of thisinvention may be employed to advantage. It is to be understood, however,that the improved apparatus of this invention may be employedeffectively as an aid to the extinguishing of an arc originating fromseparable contacts which are moved while under load whether or not suchcontacts are a part of a structure which corresponds in form to thatwhich is shown.

The switch shown in the figures noted is made up of an insulating arcenclosing housing I i having a top wall i, end walls 2 and 3, front andrear walls 4 and 5 and a bottom wall 8. The housing I l is parted alongthe juncture lines 8, 9 and E9 to facilitate access to the interiorthereof.

A plurality of housings H as above described may be assembled as shownin Fig. 3 and clamped and held in place by a clamping bar l2 whichserves as well to maintain the separable parts of the housings in closedrelation. Extending upwardly through the bottom wall 6 of each housingis an opening l3 which admits a vertically actuatable movable contactcarrier I4, upon the upper end of which there is mounted an electricallyconductive, movable contact, bridge bar E5. The contact carrier Mincludes a housed spring #5 which acts to urge the bridge bar l5upwardly against a key IT engaged in a hole in the upper end of a steml8 forming a part of the carrier 56. The lower end of the stem 18 isimbedded in and rigidly held by an insulating carrier jaw l9 mountedbelow the carrier I4 as shown.

Secured to the ends of the bridge bar 15, in upwardly facing positionand in firm electrical contact with said bridge bar are movable contacts2Q composed preferably of silver alloy. The movable contacts 20 arearranged to be moved vertically by the several carriers I 4 which jointhrough the jaws 19, as shown in Fig. 3, with an actuator bar 2!,secured to the armature 22 of an actuating magnet 23.

Positioned to be engaged by the movable contacts at the upper end oftheir vertical movement are stationary contacts 24, one of which appearsin Fig. 1. The stationary contacts 24, also preferably formed of silveralloy, are electrically and mechanically secured to terminal lugs 25-25which extend upwardly to the exterior of the ,4 housings H as shown.Near the upper end of movement of the carriers 14 the movable contacts29 are brought into contact with the stationary contacts 24 and uponfurther movement of the carriers l4 the springs [6 become compressed toestablish the necessary contact pressure between the movable and thestationary contacts.

Disposed adjacent to and partially surround-- ing the gaps existingbetween the movable contacts 2B and their respective contacts 24, whenin open position, are are extinguishing assemblages, designatedgenerally by the numeral 21. As appears more clearly in Figs. 4 to '7inclusive the arc extinguishing assemblages 27 are made up of aplurality of roughly U-shaped metallic plates 28, held in open pile,spaced, parallel relation by moulded insulating columns 2e. Inaccordance with this invention the insulating columns 29, extendingtransversely of the pile formation, are composed Of an induratedcompound formed by chemical interaction, in the presence of water, ofaluminosilicic acid and alkaline earth base material such, for example.as is set forth and disclosed in United States Patents Numbers1,852,672, 1,877,960, and 1,942,770.

In accordance with said disclosures, either naturally occurring orartificially produced materials, high in aluminosilicic acid, may beemployed, such as clays or shales and the minerals halloysite orindianite as naturally occurring materials, or fly ash resulting fromcombustion in powdered form of certain coals as an artificially producedmaterial. The aluminosilicic acid is mixed in stoichiometric proportionswith magnesia or lime and then heated in the presence of water. Thecomposition may be mixed with comparatively inert fibre fillers, such asasbestos fibre, to strengthen the finished composition. The mixedmaterial is preferably briqueted under substantial pressure in moulds ofthe desired shape to produce the conformation of the article to beformed and is then subjected to heat under conditions suitable for themaintenance of the necessary water content which participates in theindurating reactions which occur. The substance resulting is, and attimes hereinafter is referred to as, hydrated alkaline earthaluminosilicate.

In constructing the arc extinguishing assemblages 21 the metallic plates28 may be placed in a suitable mould as inserts, which mould may alsoprovide a cavity for the formation of the columns 29. The mixture ofaluminosilicic acid nd al aline earth base material, with requisitewater, may then be introduced into the mould and there briqueted to formthe columns 29. The plates 28 as shown mQre clearly in Fig. 5 are cutaway at 30 to provide for vertical continuity of the column material.Suitable inserts may also be p y d to form vertical openings 3| throughwhich attachment screws 32 may be passed. The material, having been thusformed into the desired shape, may then be subjected to heat underconditions avoiding removal of water whereupon the ingredientschemically interact forming a hard tough dense dielectric substancesuitable to resist attack by are products, A}; the same timesubstantially all voids between the colm material and t plates 8 a e elminated and a strong adhesive bond is formed along the interfaces 33 byreason of the inherent properties of the re ing substances. Thisadhesive bond 5 5 0 1 s to render the assemblage 27 a rigid t y tructuresealed aga nst any substantial access of are products at and along theinterfaces 33.

The surfaces of the columns 28 indicated at 34 in Fig. 6, are, in use,exposed to attack by are products, but such attack does not result inthe formation of a carbonaceous or other conductive film because of theabsence of organic substances. Thus the assemblages 21 remain effectiveto electrically subdivide the arc and to perform the cooling andde-ionizing function intended throughout long periods of use.

In the type of switch illustrated in the drawings the current passesdownwardly through one of the lugs, for example, 25 to a contact 24,thence through a contact 20 thence horizontally across the bridge bar [5thence upwardly through a contact 20 and a contact 24 and thenceupwardly through a lug 26. This U-shaped electrical path is such as tocreate a magnetic field which, upon separation of the contacts, tends topropel the arcs which are formed outwardly into the spaces between theplates 28 of the assemblages 21, thus causing the arc to be subjected tothe extinguishing function intended. To aid in this action the plates 28are preferably formed of ferro-magnetic material which serves to orientand concentrate the flux so as to accentuate the arc propelling forces.It is contemplated, however, that are extinguishing assemblagesconstructed in accordance with this invention may employ non-magneticplates and may be positioned to receive are products propelled thereintoby means of magnetic fields arising from other circuit configurationsand from sources other than the current flow itself. The areextinguishing assemblages of this invention may also be used insituations where the arc is propelled thereinto with or without the aidof magnetic effect by convection either naturally or artificiallyinduced or by any other suitable means.

By reason of the unitary nature of the assemblages 21 they may be easilyattached a by the attachment bolts 32 and in case of damage may bequickly removed as a unit and replaced by an undamaged assemblage. It ispreferred that the arc enclosure ll itself be also formed of thematerial employed in the columns 29 of the assemblages 21 but anyinsulating material suitable for an arc enclosure may be employed toform the housing I I.

We claim:

1. In an electric switch for a plurality of phase conductors, a separatecircuit interrupter for each said phase conductor comprising aninsulating housing; a pair of spaced, stationary contacts mounted withinsaid housing; terminals connected to said stationary contacts extendingto the exterior of said housing; a movable contact bridge bar disposedwithin said housing including a pair of electrically joined, spaced,movable contacts disposed respectively in facing relation to saidstationary contacts, said bridge bar and movable contacts being movableto and from an open position providing a pair of aps between respectivestationary and movable contacts and a closed position with respectivestationary and movable contacts in engagement joining the stationarycontacts electrically in series; an actuator cooperatively engaging saidbridge bar, extending to the exterior of said housing adapted to movesaid bridge bar to and from open and closed positions; and a pair of arcextinguishing assemblages one each being disposed within said housingadjacent to and spaced from one of said gaps at the ends of said bridgebar in are receiving relation thereto, said assemblages each comprisin aplurality of spaced, substantially parallel, electrically insulated,ferro-magnetic, cooling plates disposed in open pile arrangement withthe edges of said plates facing their respective gaps, said plateshaving aligned openings therein with a columnar mounting and insulatingmember extendin therethrough, said member having integral flangesthereon disposed between and separating said plates.

2. A switch in accordance with claim 1 wherein the ferro-magnetic platesforming the arc extinguishing assemblages are substantially U- shapedand are disposed so as to be spaced from and to embrace three sides ofthe respective gaps to which the same are adjacent.

3. A switch in accordance with claim 1 in which the mounting means iscomposed of indurated, hydrated alkaline earth aluminosilicate materialengaging and supporting said ferro-magnetic cooling plates.

4. In an arc extinguishing apparatus a plurality of spaced facinginsulated metallic plates adapted to subdivide are products propelledtherebetween, each of said plates having an opening therethroughdisposed in substantial alignment with like openings in the remainingplates, and an insulating and supporting member for said plates forrigidly maintaining the spaced insulated relation thereof, said memberbeing composed of a molded insulating material formed to provide acontinuous column of said insulating material extending through saidaligned openings with flanges of said insulating material integral withsaid column spreading laterally therefrom between adjacent plates incontact with the facing surfaces of said plates.

5. In an arc extinguishing apparatus a plurality of spaced facinginsulated metallic plates adapted to subdivide are products propelledtherebetween, each of said plates having an opening therethroughdisposed in substantial alignment with like openings in the remainingplates, and an insulating and supporting member for said plates forrigidly maintaining the spaced insulated relation thereof, said memberbeing composed of hydrated alkaline earth aluminosilicate materialmolded to provide a continuous column of said material extending throughsaid aligned openings with flanges of said material integral with saidcolumn spreading laterally therefrom between adjacent plates in contactwith the facing surfaces of said plates.

6. In an arc extinguishing apparatus a plurality of spaced facinginsulated metallic plates adapted to subdivide arc products propelledtherebetween, each of said plates having an opening therethroughdisposed in substantial alignment with like openings in the remainingplates, and an insulating and. supporting member for said plates forrigidly maintaining the spaced insulated relation of the same, saidmember comprising a continuous column extending through said alignedopenings with flanges integral with said column spreading laterallytherefrom between adjacent plates in contact with the facing surfaces ofsaid plates, said member being composed of a compound formed andrendered rigid by chemical interaction of a mixture of aluminosilicicacid, alkaline earth base material and water while said reacting mixtureis in contact with said plates whereby an adhesive bond is formed be- 7tween said member and said plates during hardening thereof.

'7. An apparatus in accordance with claim 6 wherein the continuouscolumn of said insulating and supporting member is provided with anattachment opening extending longitudinally therethrough, saidattachment opening being spaced throughout its length .from said platesby material of said member.

LYNN Ii MATITHIAS HANS PETERSEN.

8 References Cited in the file of this patent UNITED STATES PATENTSNumber Name Date Corbett July 19, 1932 Bierenteld et a1. Apr. 22, 1941Power Apr. 29, 1941 Graves, Jr June 3, 1941 Bingenheimer et a1. May 8,1951 Sandin et a1 Nov. 20, 1951

